JP3558237B2 - Oblique axial piston machine - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to an oblique-axis axial piston machine which is a so-called variable displacement oblique-axis axial piston pump and motor.
[0002]
[Prior art]
Conventionally, fixed displacement type piston pumps have been used in response to demands for various discharge capacities of hydraulic oil. The fixed displacement pump is inexpensive as compared with the variable displacement pump due to its simple structure, but it is necessary to prepare many types of pumps of each discharge capacity, and a great deal of labor is required for manufacturing and stocking them.
[0003]
On the other hand, a typical prior art of a conventional variable displacement oblique shaft type axial piston pump is disclosed in JP-A-49-80602. In this prior art and other prior arts, a cylinder block having a piston hole for efficiently accommodating a piston fixed to a plurality of piston rods swingably provided on a drive shaft comes into sliding contact with a valve plate. On a side opposite to the cylinder block of the valve plate, in a plane including the axis of the drive shaft and the axis of the cylinder block, the intersection of the axis of the drive shaft and the axis of the cylinder block is perpendicular to the plane. A convex arc surface having a straight line as a central axis is formed, the convex arc surface conforms to the concave arc surface of the cover fixed to the pump housing, the valve plate is displaced, and the cylinder block is tilted to adjust the position. It is configured to be able to.
[0004]
In this prior art, there is a problem that the operation structure for positioning for tilting the valve plate is complicated and the cost is high.
[0005]
Further, in this prior art, when the tilt angle of the cylinder block is small and the tilt angle is low, the volume of the cylinder formed in the cylinder hole of the piston becomes large, so that there is a problem that the volume efficiency is reduced due to the compressibility of oil.
[0006]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION It is an object of the present invention to use a variable displacement piston machine having one type of basic structure, for example, by manual adjustment, to consolidate many sizes, greatly reduce the number of inventories, and to facilitate manufacture. To provide an improved oblique axial piston machine.
[0007]
An object of the present invention is to reduce the unnecessary cylinder volume formed in the cylinder block of the piston when the tilt angle is small, to improve the volumetric efficiency as much as possible, and to simplify the valve plate positioning operation structure, thereby reducing costs. Is to provide a variable displacement oblique shaft type axial piston pump and motor such as a motor.
[0008]
[Means for Solving the Problems]
According to the present invention, one ends of a plurality of piston rods are swingably connected to a rotating shaft 2 rotatably provided on a housing 5,
A piston 10 is provided at the other end of each piston rod,
A cylinder block 11 having a cylinder hole 12 for accommodating each piston 10 is provided in a plane including a first axis 13 of the rotating shaft 2 and a second axis 15 of the cylinder block 11 by a first axis and a second axis. 13, 15 is provided so as to be able to tilt by changing the tilt angle α,
The end on the cylinder head side of the cylinder block 11 is in spherical sliding contact with the convex spherical surface 26 of the valve plate 25 by a concave spherical surface 24 having a center 31 on the extension of the second axis 15, and each of the passages 33 for suction and discharge of hydraulic oil. , 34, a tilting axial piston machine,
(A) The valve plate 25
(A1) It has the convex spherical surface 26, has a contact plane 36 perpendicular to the second axis 15 of the cylinder block 11 on the opposite side of the convex spherical surface 26 from the cylinder block 11, and the suction passage 33 for hydraulic oil. And the discharge passage 34 for hydraulic oil are formed. The suction and discharge passages 33 and 34 are formed at the end of the cylinder hole 12 on the cylinder head side when the cylinder block 11 rotates. A valve plate body 27, selectively communicating with
(A2) a slider 28 disposed on the opposite side to the cylinder block 11 with respect to the valve plate body 27,
It has a concave contact receiving surface 37 that comes into contact with the contact plane 36, and has a convex arc surface 43 protruding on the opposite side to the cylinder block 11, and this convex arc surface 43 is within the one plane. A straight line passing through a position deviated in the tilt direction 14 in which the tilt angle α formed by the second axis 15 from the first axis 13 and increasing in the tilt direction 14 and perpendicular to the one plane is defined as the central axis 44, and along the central axis 44. Forming part of the circumference of a right circular cylinder having a uniform radius,
A first passage 38 communicating with the suction passage 33 and a second passage 39 communicating with the discharge passage 34 are formed.
A slider 28 having a support end 47 facing the tilt direction 14 in which the tilt angle α increases,
(A3) a lock pin 40 that fits into the valve plate body 27 and the slider 28 to prevent mutual rotation,
(B) A concave arc surface 46 fixed to the housing 5 and adapted to support the convex arc surface 43 of the slider 28 is formed, and has passages 78 and 79 communicating with the first and second passages 38 and 39, respectively. A cover 6,
A slanting shaft, comprising: a support means for abutting against the support end 47 of the slider 28 so as to adjustably support the support end 47 in a displacement direction 14 in which the tilt angle α increases. This is an axial piston machine.
In the present invention, the support means may include:
A female screw member provided with the housing at a fixed position in a tilt direction in which the tilt angle α is greater than that of the valve plate, and having a female screw having an axis in the one plane;
A screw rod which is screwed into the female screw of the female screw member and has a leading end abutting on the support end 47 of the slider 28.
In the present invention, the support means may include:
A hydraulic cylinder provided at a fixed position together with the housing in a tilt direction in which the tilt angle α is greater than that of the valve plate, wherein the piston has an axis in the one plane, and the tip of the piston is Abuts against the supporting end portion 47.
Further, the present invention is characterized in that the piston of the support means abuts on the head end of the hydraulic cylinder and a step opposite to the head end to perform two positionings of the piston.
[0009]
[Action]
According to the present invention, the convex spherical surface 26 of the valve plate 25 comes into sliding contact with the concave spherical surface 24 at the end of the cylinder block on the cylinder head side, and when the rotation shaft and the cylinder block rotate, the valve plate acts on the cylinder hole. Each of the oil intake and discharge passages is configured to be switched, and in particular, a convex arc surface 43 is formed on the valve plate on the side opposite to the cylinder block. The central axis of the convex arc surface includes a plane including the axis of the rotation axis and the axis of the cylinder block, that is, the plane including the tilt direction 14 in which the tilt angle α of the axis of the cylinder block with respect to the axis of the rotation axis increases. It is a straight line that passes through a position shifted in the tilt direction of the cylinder block from the axis of the rotation shaft in one plane and is perpendicular to the one plane. The radius of the convex arc surface is uniform along its central axis, that is, the convex arc surface forms a part of the peripheral surface of the right circular cylinder.
The cover fixed to the housing has a concave arc surface 46 which conforms to the convex arc surface and supports the convex arc surface. Therefore, when the valve block is displaced by the support means and the cylinder block is tilted, the interval between the piston top and the cylinder head of the cylinder hole at the time of the minimum tilt is set to the minimum value within the tilt range of the cylinder block. You can choose. Thus, unnecessary cylinder volume between the top of the piston and the cylinder hole at the time of low tilt can be reduced, and the volume efficiency can be improved.
[0010]
Further, according to the present invention, it is possible to make the margin between the top of the piston and the cylinder head of the cylinder hole a substantially constant small value over the entire range in which the cylinder block tilts.
[0011]
According to the valve plate according to the present invention, a force is applied to the valve plate in a direction in which the tilt angle is increased by the hydraulic pressure acting on the piston, that is, a force that is directed downstream in the tilt direction. What is necessary is just to comprise so that it may contact and support the downstream end part of the valve plate in the tilting direction, the structure of a support means can be simplified, and it can be made into a variable displacement type at low cost. When the piston machine of the present invention is used as a motor, the rotation speed of the cylinder block and the rotating shaft can be changed by displacing the valve plate by the support means in a state in which the operating oil is supplied at a constant flow rate.
[0012]
Further, according to the present invention, by simplifying the structure of the support means, it is possible to provide an arbitrary capacity at a low cost by using a variable displacement type oblique axial piston machine. In addition, by preparing a pump or motor having a variable capacity of only one size, many types of specifications can be collected, the number of stocks can be greatly reduced, and the production becomes easy.
[0013]
According to the present invention, the support means can be realized by a screw rod screwed into the female screw member, and the female screw member has a configuration in which a female screw is engraved on a housing or a cover fixed to the housing. And the configuration may be simplified.
[0014]
According to the present invention, a hydraulic cylinder may be used as another configuration of the support means. In particular, the hydraulic cylinder is configured such that, at two positions of the piston, the piston is connected to the head end of the hydraulic cylinder and the step on the side opposite thereto. By contact, a pump or motor having two variable displacements can be realized.
[0015]
Further in accordance with the invention, the valve plate comprises a valve plate body and a slider to facilitate manufacture, both of which abut against each other on a contact surface perpendicular to the axis of the cylinder block and a contact receiving surface. It is configured such that the angular displacement of the two in contact with and around the axis of the cylinder block is prevented by a lock pin or the like.
[0016]
【Example】
FIG. 1 is a cross-sectional view schematically showing the entire configuration of an embodiment of the present invention. A drive shaft 2, which is a rotating shaft of a variable displacement oblique shaft type axial piston pump 1, is rotatably supported by a housing 5 by a ball bearing 3 receiving a radial force and a tapered roller bearing 4 receiving a radial force and a thrust force. You. A cover 6 is airtightly fixed to an end of the housing 5. One end of a plurality of piston rods 8 is swingably connected to a shaft end 7 of the drive shaft 2 by a spherical seat 9. A piston 10 is swingably connected to the other end of each piston rod 8.
[0017]
A cylinder hole 11 for accommodating each of the pistons 10 is formed in a cylinder block 11 having an outer shape of a right column. The cylinder block 11 is provided so as to be capable of tilting by changing the angle α of the tilting direction 14 in one plane which is the plane of FIG. 1 including the axis 13 of the drive shaft 2 and the axis 15 of the cylinder block 11.
[0018]
A coaxial central hole 16 is formed in the axis 15 of the cylinder block 11, and a center rod 17 is housed in the central hole 16. The base end portion 18 of the center rod 17 is formed in a spherical shape having a center on the axis 15 and is swingably connected to a spherical seat 19 formed on the shaft end 7 of the drive shaft 2. Each axis of the cylinder hole 12 in which each of the plurality of pistons 10 is stored is parallel to the axis 15 in a plane including the axis 15 of the cylinder block 11.
[0019]
A coaxial spring storage hole 20 is formed in the center rod 17, and a compression spring 21 is stored in the spring storage hole 20. One end of the spring 21 contacts the end of the center rod 17 near the base end 18, and the other end contacts the end 22 of the cylinder block 11 on the cylinder head side.
[0020]
The cylinder 12 in the cylinder block 11 communicates with a passage 23 formed at an end 22, and a concave spherical surface 24 formed at the end 22 comes into spherical contact with a convex spherical surface 26 of a valve plate 25. The valve plate 25 includes a valve plate main body 27 having the convex spherical surface 26, and a slider 28 holding the valve plate main body 27.
[0021]
The concave spherical surface 24 formed at the end 22 of the cylinder block 11 has a center 31 on an extension of the axis 15 which intersects the axis 13 of the drive shaft 2 at a position indicated by reference numeral 29 in one plane of FIG. It has a spherical surface. The convex sphere 26 formed on the valve plate body 27 of the valve plate 25 fits closely to the concave sphere 24 and has the same center 31 as the concave sphere 24. In this manner, the spherical surfaces 24 and 26 of the unevenness are in sliding contact with each other.
[0022]
FIG. 2 is a front view of the valve plate 25. In the valve plate main body 27, a suction passage 33 for hydraulic oil is formed on the upstream side in the rotation direction 32 of the drive shaft 2 and the cylinder block 11, and a discharge passage 34 is formed on the downstream side. The passages 33 and 34 are connected to tanks and actuators via passages formed in the slider 28 and the cover 6 (for example, 38 and 39 in FIG. 3 and 78 and 79 in FIG. 4 described later). Each of the passages 33 and 34 selectively communicates with the passage 23 on the cylinder head side of the cylinder hole 12 when the cylinder block 11 rotates, so that the pump operates.
[0023]
FIG. 3 is an exploded perspective view of the valve plate 25. The valve plate body 27 has a contact plane 36 perpendicular to the axis 15 of the cylinder block 11 on the opposite side of the convex spherical surface 26 from the cylinder block 11 (to the right in FIG. 1). The contact plane 36 comes into surface contact with the concave flat contact receiving surface 37 of the slider 28 and comes into contact therewith. Passages 38 and 39 communicating with the suction passage 33 and the discharge passage 34 are formed facing the contact receiving surface 37. The lock plate 40 is fitted into the holes 41 and 42 of the valve plate main body 27 and the slider 28, so that the rotation of the two 27 and 28 is prevented.
[0024]
On the slider 28 of the valve plate 25, a convex arc surface 43 is formed on the side opposite to the cylinder block 11. The convex arc surface 43 has a central axis indicated by reference numeral 44 in FIG. 1 and has a uniform radius along the central axis 44, that is, forms a part of the peripheral surface of the right circular cylinder. The center axis 44 is a tilt direction 14 of the cylinder block 11 that is a direction in which the tilt angle α formed by the axis 15 of the cylinder block 11 from the axis 13 of the drive shaft 2 increases in the one plane which is the plane of FIG. It is a position displaced upward (upward in FIG. 1) and is a straight line perpendicular to the one plane. The central axis 44 is, in this embodiment, perpendicular to the axis 13 of the drive shaft 2 and on the opposite side (left side in FIG. 1) of the valve plate 25 with respect to the imaginary plane containing the aforementioned center 29.
[0025]
FIG. 4 is a front view of the cover 6. A concave arc surface 46 is formed on the surface of the liner 72 facing the valve plate 25 of the cover 6. The concave arc surface 46 fits and makes a surface contact with the convex arc surface 43 of the valve plate 25, and allows the valve plate 25 to tilt together with the cylinder block 11.
[0026]
An end portion 47 of the valve plate 25 on the downstream side of the tilt direction 14 (upper side in FIG. 1) of the slider 28 is a contact plane.
[0027]
Support means 48 for supporting the valve plate 25 so as to adjust the displacement is provided in association with the housing 5. In the support means 48, a female screw 49 is formed. The female screw 49 has an axis 50 in the one plane, which is the plane of FIG. The female screw 49 and its vicinity constitute a female screw member in the claims.
[0028]
The distal end 52 of the threaded rod 51 screwed into the female thread 49 abuts against the abutting plane of the end 47 of the slider 28 of the valve plate 25 and is centered on the same axis 50 as the female thread 49 of the threaded rod 51. And a supporting spherical surface formed in a convex spherical shape. A lock nut 54 is screwed into the screw rod 51 outside the housing 5.
[0029]
FIG. 5 is a diagram showing a force when the valve plate 25 is supported by the support means 48. When the drive shaft 2 rotates, the force F1 along the axis 15 of the cylinder block 11 acts on the concave arc surface 46 of the cover 6 by the hydraulic pressure of the hydraulic oil. As a result, the slider 28 of the valve plate 25 is provided with the intersection 58 between each of the concave and convex circular arc surfaces 43 and 46 and the axis 15 and the center axis 44 of the circular arc surfaces 43 and 46 as shown in FIG. A reaction force F2 acts on a straight line 59 on the one plane. As a result, a small force F3, which is the resultant of the forces F1 and F2 and less than the forces F1 and F2, acts on the slider 28 and thus the valve plate 25. This resultant force F3 has an upward direction in FIG. The tip 52 of the screw rod 51 comes into contact with the end face 47 of the slider 28 and receives the resultant force F3.
[0030]
In this embodiment, since the support means 48 can be realized with a simple configuration, the specifications of various fixed displacement pumps can be realized by a single variable displacement pump by manually adjusting the screw rod 51. And this can significantly reduce inventory.
[0031]
FIG. 6 is a simplified cross-sectional view showing a state when the tilt angle α in the embodiment shown in FIGS. 1 to 5 is minimized. In the state in which the valve plate 25 is displaced downward in FIG. 6 by the action of the screw rod 51 and adjusted, the central axis 44 of the concave and convex arc surfaces 43 and 46 coincides with the center 29 of the cylinder block 11. In comparison, the cylinder volume formed in the cylinder hole 12 of the piston 8 can be reduced, and thus the volume efficiency can be improved. By appropriately selecting the position and radius of the central axis 44 of these arc surfaces 43 and 46, the cylinder volume between the top of the piston 8 and the cylinder head is minimized within the range of the tilt angle of the cylinder block 11. And a substantially constant value.
[0032]
FIG. 7 is a sectional view showing the structure of a support means 61 according to another embodiment of the present invention. The hydraulic cylinder 62 constituting the support means 61 is fixed to the housing 5. The piston 63 has an axis 64 in the same plane as the paper surface of FIG. 1 in the same manner as the screw rod 51 in the above-described embodiment, and the tip 65 is a convex spherical surface having a center on the axis 64. ing. The piston 63 has a flange 66 and is shown by a first position shown in FIG. 7 abutting the head end 67 of the hydraulic cylinder 62 and an imaginary line 73 abutting a step 68 opposite the head end 67. The second position is determined. Pressure oil is supplied to the hydraulic chamber 69 from the pump 70 via the switching valve 71, and the second position can be maintained. Other configurations are the same as those of the above-described embodiment.
[0033]
The invention can be practiced not only with pumps, but also with motors.
[0034]
【The invention's effect】
According to the present invention, the central axis of the convex arc surface supported by the cover of the valve plate is the rotational axis within a plane where the angle α in the tilt direction is changed including the rotational axis and each axis of the cylinder block. Is shifted from the axis of the cylinder block in the tilt direction of the cylinder block, the cylinder volume formed in the cylinder hole of the piston when the tilt angle is small can be reduced, and the volume efficiency can be improved.
[0035]
Further, according to the present invention, since a force acts on the valve plate in the one plane in the tilt direction in which the tilt angle increases, the valve plate may be configured to support the force by the support means. It is possible to adjust and change the position of the valve plate, that is, the discharge flow rate of the hydraulic oil in the pump, and also the change in the rotation speed of the motor with a support means having a simple configuration such as a rod or a hydraulic cylinder.
[0036]
In addition, by using the support means having such a simple configuration, only one kind of one-size variable-capacity oblique-axis axial piston machine is produced and prepared. And the stock quantity can be greatly reduced.
[0037]
Further, according to the present invention, the valve plate can be configured by combining the valve plate body and the slider, thereby facilitating manufacture.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing the entire configuration of a variable displacement oblique shaft type axial piston pump according to one embodiment of the present invention.
FIG. 2 is a front view of the valve plate 25. FIG.
FIG. 3 is an exploded perspective view of the valve plate 25.
FIG. 4 is a front view of the cover 6;
FIG. 5 is a diagram for explaining a force acting on a valve plate 25;
FIG. 6 is a simplified partial cross-sectional view showing a state when the tilt angle of the cylinder block 11 in the embodiment shown in FIGS. 1 to 5 is minimized.
FIG. 7 is a sectional view showing a configuration of a support means 61 according to another embodiment of the present invention.
[Explanation of symbols]
2 Drive shaft 5 Housing 6 Cover 8 Piston rod 10 Piston 11 Cylinder block 12 Cylinder holes 13, 15 Axis line 14 Tilting direction 16 Center hole 17 Center rod 20 Spring storage hole 21 Compression spring 24 Concave sphere 25 Valve plate 26 Convex sphere 27 Valve Plate body 28 Slider 31 Center 33 Suction passage 34 Discharge passage 36 Contact surface 37 Contact receiving surface 43 Convex arc surface 44 Center axis line 46 Concave arc surface 47 End portions 48, 61 Support means 49 Female thread 52 Tip portion 63 Piston 66 Flange

Claims (4)

One ends of a plurality of piston rods are swingably connected to a rotating shaft 2 rotatably provided on the housing 5,
A piston 10 is provided at the other end of each piston rod,
A cylinder block 11 having a cylinder hole 12 for accommodating each piston 10 is provided with a first axis and a second axis in one plane including a first axis 13 of the rotating shaft 2 and a second axis 15 of the cylinder block 11. 13, 15 is provided so as to be able to tilt by changing the tilt angle α,
An end of the cylinder block 11 on the cylinder head side is spherically in sliding contact with the convex spherical surface 26 of the valve plate 25 by a concave spherical surface 24 having a center 31 on the extension of the second axis 15, and each of the passages 33 for suction and discharge of hydraulic oil. , 34, a tilting axial piston machine,
(A) The valve plate 25
(A1) having the convex spherical surface 26, having a contact plane 36 perpendicular to the second axis 15 of the cylinder block 11 on the opposite side of the convex spherical surface 26 from the cylinder block 11, and And the discharge passage 34 for hydraulic oil are formed. The suction and discharge passages 33 and 34 are formed at the end of the cylinder hole 12 on the cylinder head side when the cylinder block 11 rotates. A valve plate body 27, selectively communicating with
(A2) a slider 28 disposed on the opposite side to the cylinder block 11 with respect to the valve plate body 27,
It has a concave contact receiving surface 37 that comes into contact with the contact plane 36, and has a convex arc surface 43 protruding on the opposite side to the cylinder block 11, and this convex arc surface 43 is within the one plane. A straight line passing through a position deviated in the tilt direction 14 in which the tilt angle α formed by the second axis 15 from the first axis 13 and increasing in the tilt direction 14 and perpendicular to the one plane is defined as the central axis 44, and along the central axis 44. Forming part of the circumference of a right circular cylinder having a uniform radius,
A first passage 38 communicating with the suction passage 33 and a second passage 39 communicating with the discharge passage 34 are formed.
A slider 28 having a support end 47 facing the tilt direction 14 in which the tilt angle α increases,
(A3) a lock pin 40 that fits into the valve plate body 27 and the slider 28 to prevent mutual rotation,
(B) A concave arc surface 46 fixed to the housing 5 and adapted to support the convex arc surface 43 of the slider 28 is formed, and has passages 78 and 79 communicating with the first and second passages 38 and 39, respectively. A cover 6,
A slanting shaft, comprising: a support means for abutting against the support end 47 of the slider 28 so as to adjustably support the support end 47 in a displacement direction 14 in which the tilt angle α increases. Axial piston machine. The support means
A female screw member provided in a fixed position together with the housing in a tilt direction in which the tilt angle α is greater than the valve plate, and having a female screw having an axis in the one plane;
2. The oblique axial piston machine according to claim 1, further comprising a screw rod screwed into the female screw of the female screw member, and having a tip portion abutting on a support end portion 47 of the slider 28. The support means
A hydraulic cylinder provided at a fixed position together with the housing in a tilt direction in which the tilt angle α is larger than that of the valve plate, wherein the piston has an axis in the one plane, and the tip of the piston is 2. The oblique axial piston machine according to claim 1, wherein said shaft abuts against said support end 47. 4. The oblique axial piston according to claim 3, wherein the piston of the supporting means abuts on a head end of the hydraulic cylinder and a step opposite to the head end to perform two positionings of the piston. machine.

Images